Electrical power indicating apparatus



June 21, 1938.

o. E. DE LANG: 2,121,141

ELECTRICAL POWER INDICATING APPARATUS Original Filed Feb. 1, 1936 INVENTOR y 0.5. 01: LANGE ATTORNEY Patented June 21, 1938 UNITED STATES PATENT OFFICE ELECTRICAL POWER INDI CATING APPARATUS Owen E. De Lange, New York, N. Y., assignorto Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Original application February 1, 1936, Serial No. 61,882. Patent No. 2,097,146, dated October 26, 1937. Divided and this application February 26, 1937, Serial No. 127,878

4 Claims. (Cl. 17195) This is a division of my application, Serial No. Winding 21 of an indicating meter 28 is con- 61,882, filed February 1, 1936, now Patent No. nected in a series circuit comprising a variable 2,097,146 issued October 26, 1937, and relates to rheostat 29, battery 30, contact 12, mercury conan apparatus for expeditiously indicating variatact I3, resistance element l0, fixed resistance 5 tions in electrical power. SI, and lead 32. Winding 21 of the two-way In a preferred embodiment of the invention, relay 20 is shunted across the fixed resistance a closed receptacle is provided with a resistance 3| through a variable rheostat 40. One terminal element immersed partially in a liquid contact, of battery 4'! is connected through a single pole both of which are embodied in a circuit including switch 52 to the armature 23 while its opposite an indicating meter and a battery. Heating eleterminal is connected through heating element 10;

ments controlled by a relay in response to variaiii to contact 25 and, in addition, through heattions in a load effect displacements'of the liquid ing element [1 to contact 26. contact whereby relatively large changes in the A source of electrical power 43 supplies current resistance in the metering circuit are produced. to a series circuit including the source 43, wind- These resistance changes vary in correspondinging 22, and a load 44. Variations in the magn 1y large amounts the current which actuates the tude of the current flowing in this circuit are remeter to indicate the load variations relative to a corded on the meter 28 in a manner that will predetermined magnitude. now be explained.

It is an object of the invention to produce As a pr lim n ry p to h operation of he relatively large readings of relatively small vari- C C l t, a pointer 45 iS brought to a predeter- 20 ations in the power supplied to an electrical cir mined or normal position on the chart associated cult. with the meter 28. This is accomplished by ad- 'I'he drawing is a diagrammatic circuit illusjusting rheostat 29, and represents a desired or trating power indicating apparatus constructed normal magnitude of current in the load circuit.

in accordance with the invention. Variations in load current are thereafter indi- In the preferred form of the invention illuscated as increases and decreases with respect to trated in the drawing, a resistance element In is the normal magnitude. A portion of the current disposed internally of the left vertical leg of a flowing in the winding 21 will also flow in wind- U-tube H. An electrical contact member I2 is ing 2! of the relay 20. Adjustments of rheostats secured internally of the horizontal leg at a point 29 and will therefore enable sufficient current 3 substantially equidistant from both vertical legs to flow in winding 2| to balance a normal curof the U-tube. A mercury contact 13 connects rent in Wi 22 so as to allow the p er the resistance element In and the contact memto remain in the predetermined position. Durber l2. Formed on the end of the left vertical ing this step the switch 42 is opened to preclude 3-5- leg of the U-tube is a bulbous portion 14 and on the possibility of battery 4| energizing the heat- 35 the right vertical leg is a bulbous portion [5. ing elements.

Heating elements l6 and I1 encircle the bulbous In Operation, the w tch 42 is Closed to connect portions l4 and I5, respectively. A suitable inbattery 4! to one terminal of each of the heatert gas or fluid is provided in each bulbous poring elements. In the event of an increase in the to tion to engage the mercury contact. current flowing in the winding 22, armature 23 4,0

A two-way relay 2!] comprises windings 2| and will be caused to engage contact 26 to complete 22 having positioned therebetween an armature through battery 4| an energization circuit for 23 pivoted at 24 and spaced equidistant from heating element IT. This expands the gas in the contacts 25 and 26 associated with the heating bulbous portion 15 to increase the pressure on elements l6 and II, respectively. The windings the u y Contact in the right leg of the U- 45 2! and 22 are so arranged that current flows tube causing the mercury contact to rise in the therein in opposite directions. It is to be underleft leg. This immerses the resistance element stood that when these currents are of equal value It to a r er ext nt than under a normal conthe armature 23 remains in a neutral position t Consequently, the resistance of the inwhich is indicated in the drawing; and further dicating meter C r uit s re to permit an 50. that when the current flowing in winding 2| is increased current to flow in the winding 21 and the larger the armature 23 is actuatedto engage also in the winding 2|. contact 25, and when the current flowing in The pointer 45 is actuated until the current winding 22 is the larger the armature 23 is driven in winding 2| has increased a sufficient amount to engage contact 26. 1 to balance the current in winding 22 whereupon 5'5- armature 23 is returned to its neutral position and the actuation of pointer 45 is terminated. It is obvious that the increased current in winding 2| is due to the increased current occasioned by the decrease in the resistance of the circuit including the indicating meter 28.

The return of armature 23 to its neutral position interrupts the previously formed energization circuit for heating element 1 I, hence there will be no further expansion of the gas in the bulbous portion l5. Accordingly, the resistance determined by the extent of the immersion of the resistance element In in the mercury contact will remain substantially constant until the gas in the bulbous portion l5 cools to equalize the pressure exerted by the gas in the bulbous portion I4. Obviously, further increases in the current in the load 44 are indicated as described above.

In the event of a decrease in the current flowing in winding 22, armature 23 will engage contact 25 to complete through battery 4| an energization circuit for heating element [6. This causes an expansion of the gas in the bulbous portion I 4 to increase the pressure on the mercury contact in the left leg of the U-tube. The mercury contact recedes thereby lessening the immersion of the resistance element l0 therein. This increases the resistance in the indicating meter circuit.

The increased resistance reduces the current flowing in the actuating winding 2'! and also in the winding 2|, hence the pointer 45 is actuated in a direction opposite to that mentioned above for an increased load current. This actuation continues until the current in the winding 21 has decreased an amount adequate to balance the current in winding 22. Under this balance, actuation of the pointer 45 is arrested and the armature 23 returns to its neutral position to interrupt the previously formed energization circuit for heating element 16. The expansion of the gas in bulbous portion I4 is terminated, hence the resistance determined by the extent of the immersion of the resistance element ID in the mercury contact will remain substantially constant until the gas in the bulbous portion I4 cools to equalize the pressure exerted by the gas in the bulbous portion l5. Obviously, further decreases in the current flowing in the load are indicated as described above.

It is to be understood that movements of the pointer 45 on the chart associated with the meter 28 will be in such directions as to indicate increases and decreases with respect to the normal load current.

It is seen therefore that by properly proportioning the elements of the apparatus, relatively slight variations in current flowing in the load 44 can be reflected as relatively large changes in the current flowing in the winding 21 of the meter 28. Thus, the apparatus may be utilized to indicate relatively smaller variations in current than could be indicated by the meter 21 functioning by itself. At the same time, the apparatus obviates devices employing delicate and intricate mechanical movements.

While the embodiment is illustrated to record variations in current, it is not necessarily limited thereto and can be readily adapted to record variations in potential. To accomplish this, the several circuit elements are selected to respond to potential rather than to current changes.

It is understood that the invention is capable of modifications other than the one disclosed herein and the scope thereof together with such modifications is defined in the appended claims.

What is claimed is:

1. In an electrical indicating apparatus, the combination comprising a load, an indicating circuit including in series an indicator, a source of energy, a resistance element and a liquid contact immersing the resistance element; a tube containing the resistance element and liquid contact and terminating in a sealed bulbous portion on each of two opposite ends, an expansible fluid in each bulbous portion to vary the immersion of the resistance element in the liquid contact, a heater disposed on each bulbous portion to vary the volume of the expansible fluid, a source of energy for the heaters, and means connected to the load and indicating circuit and responsive to variations in the load to connect one of the heaters to the source of energy associated therewith to vary the resistance in the indicating circuit and thereby the readings of the indicator.

2. In an electrical indicating apparatus, the combination comprising a load, an indicating circuit comprising in series an indicator, a source of energy, a resistance element and a liquid con tact immersing the resistance element; a tube containing the resistance element and liquid contact and terminating in a sealed bulbous portion on each of two opposite ends, an expansible fluid in each bulbous portion to vary the immersion of the resistance element in the liquid contact, a heater disposed on each bulbous portion to vary the volume of the expansible fluid, a source of energy for the heaters, and electromagnetic means connected to the indicating circuit and the load and responsive to variations in the load to connect one of the heaters to the source of energy associated therewith in a manner such that increases in the load cause proportional decreases of resistance in the indicating circuit and decreases in the load cause proportional increases in the resistance of the indicating circult to respectively produce increased and decreased readings on the indicator.

3. In an electrical indicating apparatus, the combination comprising a load, an indicating circuit comprising in series an indicator, a source of energy, a resistance element and a liquid contact immersing the resistance element; a tube containing the resistance element and liquid contact and terminating in a sealed bulbous portion on each of two opposite ends, an expansible fluid in each bulbous portion to vary the immersion of the resistance element in the liquid contact, a heater disposed on each bulbous portion to vary the volume of the expansible fluid, a source of energy for the heaters, and a twocontact electromagnetic relay having an armature connected to the heater source of energy and associated with each of the two contacts and including two windings one of which is connected in series with the load and associated with one contact and the second winding is connected in shunt of the indicating circuit and associated with the second contact, the power in said second winding and indicating circuit being initially adjusted so that a predetermined load causes between the two windings an effect that balances the armature substantially midway between the two contacts and produces a predetermined reading on the indicator so that variations in the load cause between the two windings eifects that upset the balance to actuate the armature to engage one of the two contacts to energize the heater associated therewith to expand the fluid to vary the resistance in the indicating circuit to produce on the indicator readings corresponding to the variations in the load.

4. The combination in the electrical indicating apparatus according to claim 3 in which an increase in the load causes between the windings an efiect that actuates the armature into engagement with the one contact to decrease the resistance in the indicating circuit thereby producing on the indicator a reading above the predetermined reading and a decrease in the load causes between the windings an efiect that actuates the armature into engagement with the second contact to increase the resistance in the indicating circuit thereby producing on the indicator a reading below the predetermined readmg.

OWEN E. DE LANGE. 

